Investigation of roles and mechanisms of DNA and histone modification networks in trans-generational epigenetic inheritance

DNA和组蛋白修饰网络在跨代表观遗传中的作用和机制研究

基本信息

批准号：
9335409
负责人：
Yang Shi
金额：
$ 40.36万
依托单位：
BOSTON CHILDREN'S HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-08-19 至 2020-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9335409
关键词：
Address Adenine Adenosine Affect Angelman Syndrome Animal Model Architecture Attention Binding Proteins Biochemical CRISPR/Cas technology Caenorhabditis elegans Cell physiology ChIP-seq Chemicals Chromatin Chromatin Structure Cytosine DNA DNA Methylation DNA Modification Process Development Disease susceptibility Engineering Enzymes Epigenetic Process Event Female Fertility Foundations Gene Expression Gene Expression Regulation Generations Genetic Transcription Genome Stability Genomics Germ Cells Heritability Histone H3 Histones Homologous Gene Human In Vitro Infertility Inheritance Patterns Inherited Investigation KDM1A gene Length Longevity Lysine Macromolecular Complexes Malignant Neoplasms Mammals Mass Spectrum Analysis Mediating Methylation Methyltransferase Modification Molecular Obesity Organism Outcome Phenotype Play Positioning Attribute Proteins Reader Regulation Role Site Sterility System Testing Work epigenetic memory epigenetic regulation experimental study fascinate genome-wide genome-wide analysis histone modification human disease in vivo insight male mutant novel programs protein purification telomere trait transgenerational epigenetic inheritance transmission process

项目摘要

Summary: Most heritable information is transmitted by DNA, following Mendelian inheritance patterns; but some traits, such as longevity, fertility, disease susceptibility, and obesity, can be inherited non-genetically in several model organisms. The underlying molecular mechanisms of trans-generational epigenetic transmission remain unclear, but chromatin changes may play a role. Chromatin is composed of DNA and histone proteins, both of which are extensively chemically modified. These modifications are recognized by so called “reader” proteins, and they regulate chromatin structure and function, together with the enzymes that add and remove modification marks. Previous work identified a fascinating trans-generational epigenetic inheritance phenomenon in C. elegans, whereby worms lacking spr-5, the human homolog of the histone H3K4me2 demethylase LSD1, do not exhibit sterility initially; however, successive generations lacking spr-5 display increasing infertility concomitant with global accumulation of H3K4me2. This progressive phenotype can be reversed by introducing a single copy of SPR-5, but how this epigenetic memory is transmitted across generations is still unknown. In many species DNA methylation at the 5th position of cytosine (5mC) is well- documented as one of the major regulatory mechanisms of epigenetic inheritance. However, 5mC is absent in C. elegans, as is the enzymatic machinery that installs methylation on cytosine, raising the question as to how epigenetic inheritance is accomplished in species such as C. elegans that lack cytosine methylation. Our recent work has uncovered an exciting new facet to epigenetic inheritance in C. elegans: we have discovered a novel DNA modification-- methylation of adenine at the 6th position (6mA)-- and have also identified the enzymes responsible for adding and removing this mark. Interestingly, this modification accumulates over the generations in mutants lacking SPR-5, paralleling the increase in H3K4me2 and the decrease in fertility, suggesting that 6mA participates in a network of epigenetic interactions that regulate germline immortality. However, little is known about how 6mA is regulated, its mechanism of accumulation in spr-5 mutants, or its role in regulating gene expression or chromatin architecture in a manner that affects fertility in spr-5 mutants. In this application, we will investigate the genome-wide distribution of 6mA (paying special attention to its accumulation in late-generation spr-5 worms) and its effects on transcription in wild-type and spr-5 mutants; determine the sites of action of the 6mA methyltransferase and demethylase as well as their means of regulation, particularly in the context of maintaining fertility; and finally identify proteins that recognize 6mA to promote downstream events such as appropriate germline gene expression programs. The proposed studies are built upon the recent discovery of 6mA and are expected to elucidate an unappreciated mode of gene regulation, providing insight into mechanisms that control epigenetic inheritance and informing studies in other species.

概括：遵循Mendelian的继承模式，DNA传递了大多数可遗传的信息。但是有些特征，例如寿命，生育能力，疾病敏感性和肥胖症，可以在多种模型中非基因遗传有机体。跨代表观遗传传播的基本分子机制仍然存在不清楚，但是染色质变化可能起作用。染色质由DNA和组蛋白组成，两者都广泛化学修饰。这些修饰是由所谓的“读取器”蛋白所识别的，它们调节染色质结构和功能，以及添加和去除的酶修改标记。先前的工作确定了引人入胜的跨代表观遗传遗传秀丽隐杆线虫中的现象，蠕虫缺乏spr-5，是组蛋白H3K4me2的人类同源物脱甲基酶LSD1，最初不存在不育；但是，缺乏SPR-5显示的成功几代人与H3K4ME2的全球积累相关的不孕症增加。这种进行性表型可以是通过引入SPR-5的单个副本来逆转，但是如何在跨越这种表观遗传记忆几代人仍然未知。在许多物种中，胞嘧啶（5MC）的第五位置的DNA甲基化良好被记录为表观遗传遗传的主要调节机制之一。但是，5MC不存在秀丽隐杆线虫，以及在胞嘧啶上安装甲基化的酶促机器也提出了有关如何如何表观遗传遗传是在缺乏胞嘧啶甲基化的秀丽隐杆线虫等物种中完成的。我们最近的工作发现了秀丽隐杆线虫的表观遗传遗传的令人兴奋的新方面：我们有发现了一种新型的DNA修饰 - 在第六位（6mA）处腺嘌呤的甲基化 - 也具有确定了负责添加和删除此标记的酶。有趣的是，这种修改在缺乏SPR-5的突变体中积聚，与H3K4me2和生育能力的降低，表明6MA参与了调节的表观遗传相互作用网络种系永生。但是，对6mA的调节方式知之甚少，其积累机理 SPR-5突变体或其在控制基因表达或染色质结构中的作用，以影响 Spr-5突变体中的生育能力。在此应用中，我们将研究6MA的全基因组分布（付款）特别注意其在后期Spr-5蠕虫中的积累）及其对野生型转录的影响和Spr-5突变体；确定6MA甲基转移酶和脱甲基酶的作用部位以及他们的监管手段，特别是在维持生育的情况下；并最终确定蛋白质认可6MA以促进下游事件，例如适当的种系基因表达程序。这拟议的研究是建立在最近发现6MA的基础上的，有望阐明未欣赏的基因调节模式，提供对控制表观遗传遗传和告知的机制的见解在其他物种中的研究。